<template lang="">
    <div class="helper">
        <span class="left"> {{unFinisedTodoLength}} items left</span>
        <span class="tabs">
            <span v-for="state in states" 
                :key='state' 
                :class="[state,filter === state ? 'actived':'']"
                @click = 'toggleFilter(state)'    
            >{{state}}</span>
        </span>
        <span class="clear" @click="clearAllCompleted">Clear completed</span>
    </div>
</template>

<script>
export default {
    props:{
        filter:{
            type:String,
            required:true,
        },
        todos:{
            type:Array,
            required:true
        }
    },
    data(){
        return {
            states:[
                'all','active','completed'
            ]
        }
    },
    computed:{
        unFinisedTodoLength(){
            return this.todos.filter(todo => !todo.completed).length
        }
    },
    methods:{
        clearAllCompleted(){
            this.$emit('clearAllCompleted')
        },
        toggleFilter(state){
            this.$emit('toggle',state)
        }
    }
}
</script>

<style lang="stylus" scoped>
.helper
    font-weight 100
    display flex
    justify-content space-between
    padding 5px 0
    line-height 30px
    background-color #ffffff
    font-size 14px
    font-smoothing antialiased
.left, .clear, .tabs
    padding 0 10px
.left .clear
    width 150px
.left
    text-align center
.clear
    text-align right
    cursor pointer
.tabs
    width 200px
    display flex
    justify-content space-between
    *
        display inline-block
        padding 0 10px
        cursor pointer
        border 1px solid rgba(175,47,47,0)
        &.actived
            border-color rgba(175,47,47,0.4)
            border-radius 5px
</style>